


When Worlds Collide

by silveryink



Category: Doctor Who (2005), Marvel Cinematic Universe, The Avengers (Marvel Movies)
Genre: Alternate Universe, Alternate Universe - Canon Divergence, Asexual Doctor (Doctor Who), Awesome Donna Noble, Crossover, Dimension-Hopping Rose, Episode Fix-It: s04e13 Journey's End, Genderfluid Loki (Marvel), Genius Shuri (Marvel), Multi, Not Avengers: Infinity War Part 1 (Movie) Compliant, Not that obvious but, Other Additional Tags to Be Added, Reunions
Language: English
Status: Completed
Published: 2019-08-27
Updated: 2019-10-18
Packaged: 2020-09-28 00:10:17
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 14,357
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20416643
Author URL: https://archiveofourown.org/users/silveryink/pseuds/silveryink
Summary: Two ways for the universe to end, two teams to save it all. In another timeline, things went rather differently for all of them. Together, though, they're unstoppable.





	1. Chapter 1

The Statesman had just entered its night cycle. The people of Asgard had been flying though space for about a month now, and tensions were rising between her citizens. With a newly crowned king, his most trusted advisor, and a scary Valkyrie who preferred to go by the same title, it was somewhat possible to keep small fights from turning over into far more serious issues. However, it was only possible to keep people who’d been cooped up in a common and somewhat tight space under check for so long. The Odinsons and Valkyrie had had to break up at least three fights that day alone, and they all knew that it was only about to get worse.

It helped that Thor and Loki started taking shifts so that one of them was always watching over the people, who’d unanimously supported their leadership, something that had come as a pleasant surprise to both brothers, who’d been expecting some naysayers at the very least. They had enough rations to last another three months, Korg had confirmed the day before, but the lack of space despite the lavish chambers that had been divided to make more room with some semblance of privacy seemed to be getting under the people’s nerves.

Thor’s shift ended at the beginning of the ship’s night cycle, and Loki had been up for an hour at least to train with Valkyrie. It helped them get some edge off their restlessness, and he ended up learning quite a few techniques with daggers that had been taught to the old legion that he’d grown up around stories of. Thor preferred to train with Hulk in the atrium, because Loki and Valkyrie had teamed up just about once to assure him that it was a bad idea for them to do so in what they’d dubbed the training room. Thor had, after a moment, agreed, and Loki had gone back to vaguely annoying the former scrapper at any given opportunity.

That particular day, Valkyrie had turned in earlier, so Loki had wandered around for a bit and, on a strange impulse, started updating the census they were working on. By the time he was back in his shared chambers (which were just about entirely unused due to his and Thor’s horrible schedules), he had just enough time to sit down and maybe get a cup of that caffeine-filled abomination to keep him up (it wasn’t coffee, or anything remotely close to it. Thor insisted that it was an energy drink, but it didn’t entirely seem to be that either. He decided after asking around for a bit that he didn’t want to know).

He was just thinking of using a spell to turn it into coffee – which he wasn’t too fond of, but it tasted considerably better than the liquid monstrosity he was about to make – when a familiar figure appeared in front of him with a bright flash of light. He raised an eyebrow and converted the residual energy into magical power, which he would later use to fuel the ship (he was already doing so with the Tesseract, but his brother didn’t need to know that).

“Not that it isn’t a pleasure to see you, but what exactly are you doing in a ship that’s been floating in the middle of space for an undetermined number of cycles?” Oh, Norns, he’d started counting days in the ship’s own cycles. He really was nearing the end times, he lamented internally.

“Where and when exactly am I?” Rose Tyler asked him, fidgeting with her jacket. She looked older than when he’d last seen her, and he wondered what exactly had happened for her to be travelling alone with what appeared to be a – wait.

“Is that a dimension hopper?” he asked, distracted. “I haven’t seen one of those in ages.”

She sighed, figuring that the lapse in information must be due to an out-of-sync meeting in their timelines. “It’s a long story. But you asked me to give you this when I saw you under these circumstances.”

She handed him a folded note. He scanned it quickly, before pocketing the paper. “This explains quite a bit, but not much. Right now, I have about three minutes to spare before my brother’s shift is over, so I’d appreciate a concise report.”

She wrinkled her nose lightly, but acquiesced. “The Doctor and I were separated a while ago. I was taken to a parallel world where my father was alive and worked with Torchwood because it was the only way I could stay alive, but now the stars are disappearing and I need to get back to the Doctor to warn him.”

“All this, with the addition of being reunited with your love,” he teased. Rose blushed, and he chuckled. “Relax. I’ll pass on your message if I see him before you do.”

“Oh, good, because this thing calls me back in about… thirty seconds now.” She bit her lip. “I know that this is a bit abrupt, but…”

“It’s fine, I understand. The note was enough information, for now at least. Though,” he added, “I _will_ need the whole story the next time we see each other.”

Rose nodded. “I owe you,” she said. “For this.”

He waved it away. “No, you don’t. It was rather infuriating to see you both dancing around each other in the past, so I’d be more than happy to see you reunited. That is, if you won’t be as obvious in your pining.”

“See you around,” she said, ignoring his last statement, and disappeared in another flash of energy.

He filed away this somewhat strange encounter for processing later and made his way to the atrium. He assumed correctly that his brother would have been stargazing after letting the barrier raise. Thor barely glanced at him when he entered the room, and he obliged by standing beside him in comfortable silence.

“As much as I don’t like being stuck here,” Thor said, “the view is quite nice.”

“It is,” Loki agreed. The stars were something that had caught their fascination from early childhood, one of a rather short list of shared interests that had lasted till date.

“Heimdall found the Earth’s coordinates today. We’re going to try to settle there now.”

“I still stand by staying on Vanaheim. We have friends there, and extended family who’d be willing to let us share their planet.”

“I believe my kingly status would cause a few issues, and I’d rather avoid any political mishaps while trying to build a new home for our people.”

“Your _kingly status_ has nothing to do with it.” Loki paused. “You do realise that Earth’s bureaucracy is far worse than the one on Vanaheim?”

“Whatever it is, brother, we can face it together.”

Alright, fine, the sentiment warmed him, but this was getting a little ridiculous. Loki had to bring up some points here that Thor had decisively been avoiding so far.

“Do you really think it’s a good idea to go back to Earth?”

Thor shot him a sideways look that reminded Loki suddenly of their mother. Thor had always resembled her more than their father, but it still took him by surprise sometimes.

“Of course, they love me there.”

Oh, now he was being deliberately obtuse. Despite the seriousness of the conversation they were trying to have, Loki was amused by his brother’s newly awakened sense of humour.

“Let me rephrase that,” he said, “do you really think it’s a good idea to bring _me_ back to Earth?”

Thor considered this for a while, and smiled at him after. “Probably not,” he admitted. “But don’t worry, brother, I have a feeling everything’s going to work out.”

Loki nearly gave in and smiled at his brother’s endless optimism – but a shadow fell across the room, looming over them. He raised an eyebrow at Thor. “You just _had_ to say that, didn’t you?”

* * *

The Doctor was a little stupefied by the number of times the words _Bad Wolf_ had appeared in his vicinity. That Donna also knew the words threw him off entirely. She’d explained to him in full detail what had happened, and he’d tried so hard not to visibly react when she described the nameless woman she’d met who was so very clearly Rose. Donna was perceptive, though, and she latched onto that and asked him if he knew her. Her eyes had widened in sympathy when he’d said her name. Donna knew that he’d lost her years ago, so she was quick to offer her reassurances of Rose’s return.

He smiled shakily at her, though something nagged at his instincts about the stars disappearing. That usually meant that the walls between universes were falling apart, and-

“Doctor, is that thing supposed to be blinking?”

The Doctor blinked. “What?”

“That light,” Donna elaborated, “it’s blinking at me.”

“Donna, that’s – it’s – hang on, that’s a distress call!” he hurriedly switched to the right controls that would enable the other ship to communicate with them. A few moments later, once the Doctor listened to the relayed pattern of numbers twice, he ran up to the console and started the dematerialization process.

“Doctor, what were those numbers supposed to be?”

“Spatial coordinates,” he explained. “This sequence also included temporal coordinates, so I guess they’re from someone I know. Or will know.”

“Like that archaeologist in the Library?”

“Yeah.” The Doctor threw the last lever and turned back to Donna. “See, this was a deliberate call – whoever they are, they knew to call for the TARDIS specifically. Different ships operate on different frequencies, and only a few people know this one.”

“Right,” Donna said. “That makes sense.”

“And if it is who I think it is,” the Doctor added gravely, “then I think we’ll need to be there right now.”

“So long as my face doesn’t end up on another statue,” his friend joked. The Doctor grinned sheepishly. The TARDIS shuddered, and the pair had to cling onto the railing to avoid falling over. With a final few gasps from the Time Rotor, they stilled and landed firmly where they were meant to.

* * *

A great rasping noise filled the doorway of the console room. Loki, who was currently slumped next to the navigation pane after using most of their reserves to shield the ship, grinned. Thor raised an eyebrow, but was more occupied by the camera feed that warned the siblings about the cannons that were being armed to fire at them. He’d have given them about thirty seconds before the next volley, and they were protected by shields.

The ship shook wildly as the cannons fired at the nearly empty ship, and Thor crashed into a nearby panel, some small part of him thanking the stars that his sibling was currently braced against a stable part of the panel. He groaned and blinked a few times, the raspy sound only growing louder. The last of the escape pods detached from the Statesman, and the resulting beep that announced their success managed to pull a laugh from somewhere inside him. The raspy noise was then joined by a glow, and a blue Midgardian phone box – a police box, Thor remembered from his few trips to Earth in the sixties – appeared in the centre of the glow.

The doors opened, and a lanky man with wild hair poked his head out into the room. His sharp gaze fell on Thor, and then on Loki, who had gotten to their feet shakily. The man stepped aside. “Get in.”

Thor glanced at Loki, who nodded at him. “He’s a friend,” they said, and Thor didn’t hesitate after that.

Once the doors of the box were shut behind them, Thor took a moment to marvel at the size of the interior. “It’s like your pockets,” he blurted out, and Loki chuckled.

“Dimensionally transcendent, isn’t that what you call it?” they asked the man in the brown suit.

“Well, I was kind of hoping for the usual reaction,” he said, running a hand through his hair. “Anyhow. I’m the Doctor, and this is my friend Donna.”

The woman who’d been standing by the console waved at the brothers, stepping aside so that the Doctor could send his ship into… anywhere but here. “Hi. Donna Noble, human.”

“I’m Loki, and this is my brother Thor. No, we’re not from the myths, yes, we’re from Asgard, which technically counts as an alien planet to humans.”

Donna nodded. “That’s a good introduction,” she commented.

“Well, when you get the same questions every time…”

“That would do it,” she finished with a quick grin.

“I’m afraid I cannot continue this conversation right now, but I think I should like to get to know you.” Donna nodded at their invitation eagerly.

“Right,” the Doctor said, neatly inserting himself into the conversation, “your distress call.”

Thor frowned. “Loki, when did you send a distress call?”

“When you were using the console room to play _leap_ _frog_,” they said distractedly. They’d taken a small note out of their pocket, and had been frowning over it. They nodded and slipped it back inside after sweeping a scrutinising gaze over it, seemingly to confirm what it said. “No, I’m being serious,” they added at Thor’s glare.

“What exactly was going on back there? It looked like you were stuck in a warzone.”

“That’s not entirely wrong,” Loki said, brow creasing. “We were being attacked.”

The Doctor raised an eyebrow. “You wouldn’t have called me if you’d just been attacked. No, this was different. I’m guessing… bigger threat, shady past, universal threat?”

Loki met his gaze levelly, and said one word. “_Thanos_.”

The Doctor’s eyes widened and he paled. Thor couldn’t entirely blame him; the Titan was a horror story to all Aesir children. “I – _what_? How is that possible? We’d – they’d – _agh_, he’d been locked away ages ago by the Time Lords!”

“I know,” Loki said. “But I’d just about flung myself into his prison and weakened its walls nearly a decade ago.” Thor winced at the reminder of that horrible day and was suddenly filled with relief that his sibling was alive and well by his side. Though he suspected that he was currently the one at Loki’s side – the trickster seemed to be quite in their element. Donna moved to stand beside him as the Doctor and Loki spoke in low tones.

“So, who’s Thanos?” she asked quietly.

Thor sighed. “My lady, he was a mythical figure of sorts to us, a cautionary tale. _Don’t go hunting for power_, that sort of thing. There were several versions of the story – that the Titan had gone mad after finding a solution to attain true immortality and sought a way to permanently erase himself, another where he killed his entire race… the most common tellings are the most strange. One says that he courts Lady Death, and wishes to present the souls of half the universe to her as a gift. The other says that he wishes to rid the world of half of all life, due to a universe-wide population crisis.”

“Yeah, that seems a bit strange. That’s not how resource scarcity works,” Donna mused.

Thor shrugged. “All my life, I thought they were just stories. It’s bad enough that he actually exists, I’d rather not find out _why_ he wants to carry out his dastardly plan of genocide.”

Donna nodded. “We should probably stop the end of the universe from happening, then,” she said quietly, and smiled up kindly at him. Thor felt a flicker of warm hope in his chest, like faint candlelight.

“Probably,” he agreed.

The TARDIS suddenly shook and made the familiar sounds of dematerialisation. Thor frowned and shook his head, trying to clear away the ringing in his ears. “Is it always like this?” he asked to no one in particular.

Donna shrugged. “Has been since I’ve been on here,” she said.

Loki caught Thor’s glance and nodded. “Ever since I’ve known the Doctor,” they added.

“Oi, it’s the sound of pure Time,” the Doctor said, leaning against the console and wincing when a part shocked him. The raspy noise rose in volume, and everyone winced when the cloister bell chimed once.

“It’s deafening,” Loki said, concern etched onto their face despite the sarcasm in their words.

“We’re already in the Vortex,” the Doctor mused, “so Thanos couldn’t have…”

“No, that’s well beyond his powers.” A beat, then: “You told me about that trip to Krop Tor, could this be similar-”

“Indigestion?” the Doctor interrupted speculatively, and dismissed his notion almost immediately. “Nah, can’t be. Though, before you called, I _was_ on my way to Earth. Donna’d know more about that,” he added, nodding at his friend.

The siblings looked up expectantly at her, and she looked a little daunted by all the attention. She quickly summarized her incident with the Time Beetle and the alternate timelines, even telling them about the stars going out.

“Anyway,” the Doctor concluded for her, “we got off the planet sharpish when we saw – well.”

Loki nodded. Thor inferred that this must have been discussed privately and was completely irrelevant to their next endeavours. Loki turned to him. “As much as I hate to turn down your offer of help, I’m afraid that will be a bit contradictory.”

“Contradictory how?” the Time Lord asked, frowning. Thor could relate, since he barely had a clue what was going on. His head was reeling.

Loki extracted that folded piece of paper from their pockets silently. “I can’t say what this is exactly,” they said, “but it was a message from my future self.”

The Doctor raised his eyebrows, exchanging a significant look with Donna, who seemed to have wanted to object. He nodded at Loki, who opened it up once more with a sigh.

“There is another note inside, addressed to you,” they added, slipping it over to Donna as the TARIS landed with a final, harsh gasp. “I didn’t read it, but it might answer some things.”

“’Ta,” Donna said politely, passing it over to the Doctor. “Would we be able to meet again?”

Loki shrugged, though their eyes were dancing merrily. Thor felt a little more warmth in him, the small candle flame glowing brighter. Perhaps they’d get out of this situation rather well, after all.

“I’m afraid that would be telling, Lady Noble.”

“Donna,” she corrected automatically, shaking their hand in farewell.

“Donna, it would be an honour to see you again,” Thor said, lowering his head in lieu of a proper bow as he shook her hand as well. “You as well, Doctor.”

The man in question nodded and waved lightly at them as Loki stepped off the TARDIS, looking like he was trying to prepare himself for a barrage of questions from Donna. Let her ask, Thor thought. The universe needed more people to question its unspoken laws, to be brave enough to stand up and change them. He could see why Loki might like travelling with the Doctor, now. The prospect of making a change seemed enticing, even as Thor felt his world crumbling around him, too fast and far too soon.

He suspected that Loki appreciated the chaos element of such erratic travel, though. That _would_ appeal to them, as the patron of mischief.

Thor stopped his thoughts when he bumped into his sibling, which was just about the time the TARDIS dematerialized behind them. Only then did he realise where they were, or notice the repulsors aimed directly at his sibling’s face. Tony Stark lifted up his faceplate even as Loki raised their arms in a gesture of peace (or nonviolence, because nothing was ever really _peaceful_ when Loki was involved).

“You have some explaining to do.”


	2. Chapter 2

“Well?” Donna crossed her arms over her chest and raised an eyebrow. The Doctor sighed. He’d seen this coming since he’d seen who exactly sent the distress signal. He ran the paper over and under his fingers, idly flipping it over and back again as he tried to find a way to answer her unspoken array of questions.

He could start with the easiest, he figured, and work from there.

“You heard Loki’s introduction when they came in,” he said, leaning back against the railing. “That sort of sums it up. I met them a while back when I took Rose to Asgard-”

“On a date?”

Despite himself, the Doctor fell silent. That had been before he’d regenerated, so they hadn’t quite vocalized what their relationship would be. Did she consider that trip a date? _Then again_, a voice in his mind – one of the more gracious ones – reminded him, _she called your first trip with her to see the Earth blow up a date._ His spirits brightened, and he looked up at Donna, smiling.

“Yeah,” he said, and Donna grinned before making a _go on_ gesture.

“I took Rose to see a play, and we visited the Royal Library. Only, when I tried to use the psychic paper to get inside, it didn’t work. Almost got into trouble, but Loki came up and asked to let us in. Said that knowledge shouldn’t be withheld, even from otherworlders.”

“He knew that you weren’t from Asgard?” Donna asked, surprised. Granted, the Doctor alternated between two suits, and what she’d seen the siblings wear on the TARDIS was nowhere close to the same style, but none of the others who’d met them during their journeys had commented on it. She’d supposed that it was to do with the TARDIS, or his alien-ness.

“_She_,” the Doctor corrected gently, “did. I asked her how, and she didn’t reply. Only made sure that I wouldn’t enter the archives where all the important stuff was stored. Official documents and the like.”

Donna nodded. “So did you invite her on then?”

The Doctor shook his head. “Nah. We met a few more times after that, and Rose and I invited him to travel with us.” He decided not to mention Jack now, though his lips twitched upward at the memory of how shamelessly the pair had flirted with each other.

“Right, and Thor’s his brother,” Donna added. “But what was that with the paper?”

“That’s the thing, Donna,” he said, running a hand through his hair, “It might have something to do with what we saw on Shan Yen, or it might not. And I don’t want to disrupt the timelines anyhow.”

The TARDIS lights flashed and matched Donna’s dry look perfectly. He wondered how his ship sided with his companions more than himself. Though, she _did_ love Rose as much as he did, and Donna was family. He wasn’t sure when that had happened (probably after the whole business with the Sontarans), but it wasn’t quite unwelcome.

“Right,” he muttered, unfolding the paper. In it was a series of coordinates – space-time coordinates, along with the word _Earth_ scrawled above them in vaguely familiar writing. “I don’t think this is entirely relevant,” he said with a frown. “These are coordinates, and definitely _not_ Earth’s, which would make the most sense given recent events.”

Donna shrugged. “At least you _do_ know that,” she pointed out, and he couldn’t really fault her for that.

* * *

“So let me get this right. Your brother – sorry, sibling – is innocent of their crimes because they were, what, mind controlled by the same sceptre that they used to control Clint and the rest of the agents?”

“Partly innocent,” Loki interrupted. “I was influenced by the sceptre, meaning all my actions were my own, though my motives were not.”

“So, you didn’t want to invade the planet but you did it anyway?”

Bless the mortal for trying to understand their intentions. Loki frowned, considering the question. “I didn’t want to destroy or rule your planet,” they said at last, “but I would have done it if it meant being out of Thanos’ hands.”

“And keeping the Stones out of them,” Stark muttered. He glanced up sharply at Loki. “You didn’t happen to set up the invasion to fail, did you?”

Loki grinned brightly. “Oh, you noticed.”

Tony exhaled and dragged a hand down his face. “This doesn’t mean we’re all chummy now,” he said finally. “However, I don’t want the universe to end up in a pile of ashes because one person wants to change things to his liking.”

Loki nodded. They’d take that. “Of course. I’m well aware of the consequences of my actions and – _Norns_, Thor, what is it?”

The king had been tapping at their shoulder since they’d started to reply. Tony followed his gaze, eyes widening. “Uh, yeah, Reindeer Games, I think your brother’s onto something here. I believe you, I don’t necessarily like you-”

“Yet,” Loki said automatically, turning slowly. They lifted their eyes in the general direction of where Thor was looking, and stared.

“And we can work out the details later,” Tony finished, ignoring him completely. Well, they were _also_ ignoring him, so that could be forgiven. For now.

A giant wheel-shaped ship had just appeared in the Earth’s atmosphere. Loki swore. “He literally _just_ came to the Statesman, and I know for a fact that that was at least three galaxies away.”

“Okay, now you’re pulling my leg. You arrived in a sixties’ London police box, which just disappeared after you got off.”

Thor shook his head. “Loki’s right. Thanos shouldn’t have come here this soon.”

“I don’t think that’s Thanos,” Loki said darkly, manifesting their armour – the metal-lined kind which was mostly used in battles as opposed to the leathers they’d worn on the Bifrost bridge (and ever since). “Trust me when I say, _we need to get out of here_.”

“Did this guy come after you?”

Loki shook their head. “Unlikely. He’s here for something else. Another Stone.”

“Not _Time_?” Thor asked, eyes widening as he remembered the wizard who’d summoned him into the New York Sanctum (which had changed quite a bit since the twelfth century).

His sibling’s look said it all. Thor growled low in his throat, lightning sparking across his knuckles. “We have to make sure that it doesn’t fall into their hands, then.”

“Thor, the Maw is-” the rest of their reply was swallowed by the loud churning of engines and screams of the city’s occupants who ran about dodging the flying debris. The trio ducked as part of a car sailed over their heads. “-should have left by now,” Loki finished, voice rising to a shout. “The Sanctum’s protocols say as much.”

“I know the protocols, Loki, _I helped you write them!_” Thor moved behind a pillar as Tony summoned his armour again. They’d been standing outside the Avengers Compound when they’d arrived, and by the time their conversation was over, they’d moved well into the city.

“Mr. Stark,” called a voice from above them. Stark closed his eyes, though it went unseen by the others.

“Kid, you’re supposed to be on a field trip _away_ from the city,” he said, and Loki could _feel_ the fond exasperation, along with the undercurrent of worry, practically rolling off him. They tilted their head, curious to see where this was going. Stark’s remark seemed _awfully _parental.

“Yeah, but then I saw the huge ship hover above New York,” the unnamed kid replied, landing lightly on their feet. The kid seemed to notice the Aesir for the first time. “Hi guys, I’m Spider-Man.”

Loki nodded, and Thor clapped a hand on the young hero’s shoulder in greeting. Loki might not have been to Earth in the last three years (after he’d left Odin at the old age home, and not counting the last – rather disastrous trip when they’d had to fight Hela), but he _had _been keeping up with the news.

“Good to meet you,” Thor said warmly. “I’m Thor, and this is my sibling Loki.”

“Ooh, like the god of mischief? I studied Norse mythology a few years ago – I mean, I did some light reading – and they said something about being blood brothers with Odin?”

“I’ll have to correct you on that; I’m his child and _Thor’s_ sibling.” He elbowed Thor lightly to wipe that quick grin off his face. “However, if you wish to compare notes about your stories and what _actually _happened, that will have to be a conversation for later.”

“Yeah, okay, that’s unlikely,” Stark interjected. “You can stay away from the kid.”

Loki rolled their eyes. “I’m hardly going to _attack a child_.”

“I’m… not a kid, though?” He sounded doubtful, though, even as he said it.

“No, you’re _his_ kid,” Loki said, raising an eyebrow when Stark started to splutter under his mask. “This conversation is rather amusing, but I think getting out of here should be a higher priority right now.”

“Uh, no can do, Reindeer Games, we have to protect the city.”

Loki sighed and summoned his armour. “You know, this is exactly why I never wanted to be a hero.”

* * *

Donna frowned. The Doctor, while navigating the TARDIS and scanning for peculiar phenomena, had explained much of what she hadn’t quite understood about the situation. They’d even landed on Earth, in Chiswick, she thought, and it had been a Saturday, with nothing special to it – at least, not that they knew of. Sometime in the future, there was going to be a battle that concerned the universe as a whole. Even now, she could tell that something was coming: something big and not entirely _good_. She had one last thing to ask him, though.

“The thing is, Doctor, no matter what’s happening – and I’m sure it’s bad, I get that, but…” she sighed and waited for a moment for her friend to look up at her. She needed his full attention for this. “Rose is coming back. Isn’t that good?”

The Doctor stiffened, eyes widening slightly, and just for a moment, Donna wondered if she’d said the wrong thing. Her doubts dissolved, however, when he smiled shyly at her, with that look in his eyes that meant he was thinking about his lost love. “Yeah,” he said, and she grinned at his brightening mood.

The TARDIS jolted, and she fell heavily onto the banisters. Thoroughly winded, she straightened and asked, “What the hell was that?”

“Don’t know, it came from outside.” The Doctor jogged upto the doors and threw them open, and cried out in surprise. Donna couldn’t blame him – she knew that they hadn’t moved, and yet…

“But we’re in space.” She couldn’t think of any explanation for this. “How’d it happen?”

The Doctor shoved the doors shut, moving back to peer at the console. “We haven’t moved,” he muttered, almost to himself – though Donna knew that he was addressing her. “We’re fixed, we can’t have – no, the TARDIS is still in the same place, but the Earth is gone.”

He looked up at her, looking, for the first time through their travels, completely flummoxed. “The entire planet,” he repeated. “It’s gone.”

Three things struck Donna at once. Only one of them seemed to matter at the minute, so she decided to voice that alone. No need to worry about the rest until they seemed completely relevant. “But if the Earth's been moved, they've lost the Sun. What about my Mum? And Granddad? They're dead, aren't they? Are they dead?” She somewhat regretted saying that last part – though she had to voice her fear somehow, and the Doctor was kind enough to listen and attend to them whenever he thought he could be of some help.

He ran a hand frantically through his hair. “I don’t know, Donna,” he said, worry and frustration lowering his voice to a slight growl. He sighed. “I’m sorry, I don’t know.”

Well. She hadn’t thought he did, nor did she blame him. _That’s my family_, she thought, _my whole world._ She decided not to say as much, knowing that there was no point in distressing her friend even more than he already was. She looked down and caught a sight of the paper Loki had given them, and an idea formed in her head.

“Doctor,” she said, and he looked up immediately, recognising her tone. “Those coordinates, do you think they’ll lead us to wherever Earth is now?”

The Doctor opened his mouth to speak up, and stopped. The TARDIS chimed once, lights blinking for a second in accentuation of a point. A non-verbal one, anyway. Donna knew that the ship was telepathic, and that it was possible for the Doctor to communicate with her due to his alien biology.

“D’you think so?” he murmured, and nodded. “Well, Donna, I suppose that’s what she wants us to do, anyway.”

“Well, then what are you waiting for?”

* * *

Looking at the corpse of Ebony Maw at their feet, Loki had to admit that he was considerably more at peace than he had been since this catastrophe had started. At least one of his old tormentors wouldn’t be after him now. He wasn’t particularly optimistic about their chances: they still had to look for the rest of the Avengers and warn them about this new threat. Vision in particular was in a large amount of danger, seeing as the android carried the Mind Stone in their forehead.

“Oh, that’s marvelous,” he muttered, seeing the unmarked black car roll up to where they all were leaning against a wall. “I save New York from someone who’d destroy it without a moment’s hesitation, and this is the thanks I get?”

Thor shot him a withering look. “You know, I was there too. I assume they’re with Stark, since he told us he was calling for help.”

Loki took the fact that Thor hadn’t mentioned the time he’d been the one to attack New York as a plus. He shrugged noncommittally. The car stopped beside them, and a smartly dressed woman opened the back door. Virginia Potts, he assumed. She nodded at them all formally. “We have a _lot_ of talking to do,” she told Thor and Loki, unintentionally echoing Stark’s words from when they’d just arrived at the city.

They nodded their approval, and, as they got into the car, noticed her shoot a stern look at Spider-Man. “You should be at the field trip,” she said.

Spider-Man fidgeted. “I was… otherwise occupied.”

She hummed and lowered her voice, inaudible even to Aesir (and Jotun) ears. A murmured response from the webslinger, and she climbed back inside before he used his webs to swing away from them all.

“What did you tell him?” Stark asked, amazement written all over his features. His armour had retreated, and he was nursing his left shoulder, which he’d injured by free-falling onto a building. “It’s like he only listens to you,” he grumbled a minute later, with no heat in his voice.

Miss Potts shrugged. “It will keep him away from the fighting. He’s allowed to listen to KAREN for updates, though. I had to promise him that.”

Stark nodded, and Loki internally agreed. While it wasn’t the best bargain he would have made, it was good enough for a young man like the webslinger. He hoped to see him again in the near future: the young hero seemed to be a good enough conversationalist to keep things interesting. What was more interesting to him right now, however, was the rather calm air Miss Potts had around her, especially considering New York had yet again been attacked and that she was sitting in a car with its previous attacker.

He wondered how exactly this was to go.

* * *

Rose heard a crash – specifically, the shattering of glass – and swiveled around to see two men hauling out a large television from a nearby electronics store. She pursed her lips, hoisting up her blaster in hopes of scaring them away. “Oi!” she called.

They stopped, and stared at her.

“Right, you two. You can put down that stuff or run for your lives.” When they didn’t move, she took a step closer to them. “D’you like my gun?” she asked cheerfully, having no intention of firing her weapon at them regardless of what they did.

They didn’t know that, though, so they set the unit back down and bolted. She smirked. It might not be particularly be important in the bigger image, but she’d do anything she could to help out somehow. This was _her_ world, the one she’d lived in for over twenty years, where she’d met the Doctor and fallen in love with him. The parallel world was rather nice, and Pete did his best to smooth her transition, but it lacked the feeling of _home_.

She doubted she’d properly feel it until she went into the TARDIS. If the Doctor still wanted her, that is. She wouldn’t begrudge him for taking a new companion, even in a romantic sense, but she really did need to warn him about the universes falling together. She hoped Loki and Donna had delivered their messages to the Doctor; it would certainly speed things up.

She pulled up a laptop and swiftly logged on to her Torchwood profile, figuring that since the universes were colliding it would be available here anyway. She was met by a _very_ familiar face.

Captain Jack Harkness leaped back from the screen in shock, before leaning back and squinting at it. “Rosie?”

She laughed. The world might have been ending, but _Lord_ had she missed her old friend. “Jack,” she said by way of reply. He laughed as well.

“I thought – the Doctor said you were in a, a parallel universe!”

“I was, and now I’m here.” She inhaled raggedly. “Listen, the walls between universes are crumbling. That’s how I got here. The stars were going out in the other world, the parallel one. I don’t know why, but you know exactly what that means.”

Jack nodded gravely. “Yeah. It’s not looking so good, Rosie.”

Rose made to reply, but Jack’s phone rang. He glanced at the caller ID, and brightened. “Martha Jones, voice of a nightingale. Tell me you put something in my drink.”

Rose waited as Jack connected the call through to her as well. “You’re on speaker now, Martha,” he said. “On the other end of this line, is Miss Rose Tyler.”

“Agent,” she corrected. “Currently.”

“Good to meet you, Agent Tyler. Jack, I’ve been promoted. Medical Director on Project Indigo.”

Rose hummed in appreciation. In her world, Indigo had been developed just after she’d arrived, so she knew – roughly – how it worked. Jack raised a brow at her and spoke up. “Did you get that thing working?”

“Indigo’s top secret.” Rose could practically hear the frown in her voice. “How have _both_ of you heard about it? Actually, Rose, please don’t answer that.”

She chuckled. Jack, in his true fashion, said, “Oh, I met a soldier in a bar. Long story.”

“When was that?” Rose heard someone off-screen ask. It sounded an awful lot like someone she’d met who worked at the parallel Torchwood, but…

“Strictly professional,” Jack soothed.

“Jack, are you by chance talking to Ianto Jones?” Rose asked, indulging her curiosity.

Jack blinked. “Yeah. Why, met a parallel version of him at the other Torchwood?”

“Yep.”

“That sounds about right,” Jack muttered. “What with how today’s going and all.”

“Fifteen hundred miles,” another voice broke in, “and accelerating. They’re almost here.”

“Wait,” Rose said, as the computer beeped, “There’s a signal coming through. They’re trying to communicate with us.”

“Putting it through…” Jack muttered, furiously typing away.

Hoarse, bitter voices that sounded much like someone had been gargling on metal filings and glass shards echoed through the small speakers of the laptop. Despite the distorted quality that only enhanced the pure malice in the transmission, though, Rose knew exactly who was addressing them.

“Exterminate. Exterminate. Exterminate!” the Daleks chanted, and she recoiled from the screen instinctively.

Jack had, meanwhile, pulled his friends close in a hug, and she knew that it was more to comfort him than offering it to the others (though he _would_ do that too). They were questioning him now, but Rose was distracted by a familiar grating noise. She shoved away from the laptop and ran outside, to see the TARDIS appear right before her.


	3. Chapter 3

The TARDIS doors flew open, and the Doctor tumbled out haphazardly. A red-haired woman stepped out much more cautiously, moving to his side. Rose tilted her head and smiled. Donna _had_ delivered him the message, then. The Doctor’s appearance here meant that her other message had found its way to him as well. She turned her gaze to him as he straightened and adjusted his coat, and watched his eyes flick over to the darkened sky, then over the buildings, and lastly (when Donna elbowed him), directly at her.

She shoved the blaster away to rest by her side and ran into his arms. He happened to be thoroughly unprepared to find himself with an armful of Rose, and stumbled back slightly even as he returned her hug fiercely. She heard his delighted and somewhat muffled laughter and joined in when he lifted and spun her around lightly. God, she’d finally done it – _she was back with the Doctor_.

She pulled back. The Doctor’s eyes were suspiciously shiny, and he cleared his throat. “Rose,” he began, voice hoarse with emotion, and she stopped him from having to say anything else by yanking him forward by the lapels of his coat into a kiss. His hold on her tightened, and in that moment, she knew exactly what he felt. All of his desperation, disbelief, elation, giddiness, and sheer _relief_ – standing here, in his arms, she could quell the last fears that lingered in his mind about their separation.

“Not that this isn’t a lovely reunion,” Donna said, looking in the opposite direction, “but I thought we had something else to take care of?”

“Can you really blame me, Donna?” the Doctor asked softly, when the couple broke apart without really leaving the loose embrace they’d wrapped each other in.

She sighed. “No,” she said, turning and smiling at Rose. “It’s nice to meet you outside a dream.”

“Parallel timeline,” Rose corrected. “Looks like you found your way back just fine, though.”

“And I delivered your message.” Donna shook her proffered hand. “Sorry to break up the moment, but-”

“No, you’re right,” Rose said, abruptly pulling away to drag the Doctor into a nearby electronics store. She nodded over her shoulder for Donna to follow, and Donna grinned. She really would like to get to know Rose more, once she and the Doctor had a proper reunion after this misadventure. “See, in that parallel universe I was trapped in, I joined Torchwood. ‘S easy when your father runs the place, and my knowledge of outer space was helpful enough that I became a high ranking agent quite early on.”

The Doctor, who suddenly seemed to be incapable of stringing together enough syllables to form a proper word, abandoned all his attempts at speech and beamed at her. Donna nodded at her appreciatively.

“We used the old hoppers to move across worlds, see-” she showed them the big plastic buttons - “and we made this thing, a dimension cannon, which refined our landings. It didn’t work, even though our calculations were all correct, but then the stars started to disappear.”

“The walls of the universe were crumbling,” Donna said, remembering what she had told her. “You could go through the Void, yeah.”

“Right,” she nodded encouragingly. “Apparently that means now I can access _both _Torchwood networks, so…”

“You have a line open to them?” Donna asked shrewdly.

“Yeah, I do.”

The trio could hear the transmission even from the entrance of the shop. The Doctor went rigid, blanching even more than he had when Loki had mentioned Thanos to him. Rose took his hand and squeezed it reassuringly. Donna frowned. “What…”

“Daleks,” Rose said, and Donna caught on immediately. She knew about the Daleks, though she’d never seen one herself. She’d read up on Canary Wharf after meeting the Doctor, and he’d divulged far more information than any website had (though she’d only asked once, and immediately known not to push from the utter despair in his eyes).

“Rose! Rosie, are you there? The Valiant’s down!”

The Doctor frowned, sharply moving to the screen. “_Jack_?” he asked incredulously. This day was shaping up to be rather strange. For starters, why on Earth was the Valiant’s name invoked now?

Jack didn’t reply, he was crouched over a table where the Doctor presumed the monitor was, or however the Torchwood was laid out these days. He was shouting into a phone, and the Doctor felt a chill in his spine when he realised who he was speaking to.

“They’re targeting military bases, and you’re next on the list!”

“Doctor Jones,” another voice said, off-screen, and the Doctor’s hearts skipped twin beats. No, this was too much of a coincidence, even for him. “You will come with me.”

He tuned out the rest of the orders and turned to Rose, who was hovering over his shoulder. He moved aside, noticing that she meant to use the laptop for… something. She expertly scanned the readings and typed in commands, and his heart warmed to see her in her element (a new one, which he’d have to get used to, but _hers_ nonetheless). The world could collapse with him in it and he’d still appreciate how much in love he was with Rose Tyler. The call was still on, though, and Jack swore loudly, standing upright. He spared a moment to nod at the Doctor in lieu of a proper greeting before focusing his attention on Rose.

“Martha’s taken Indigo,” he said heavily. Rose glanced at him and looked away immediately, not faltering in her search. The Doctor was perfectly fine with letting her take charge of this situation. She’d likely been preparing for it for longer than he had, and possibly anyone else on this planet. Though he did wonder what Indigo was about.

“It’s a teleport, and assuming that it works the same way as the one in Pete’s Universe, she should be fine.”

“Rose, it’s experimental. It doesn’t have stabilisation, and she doesn’t have coordinates.”

Rose shook her head. “It works on intentions. It gets less and less accurate the more it’s used, so you’d have to switch to manually changing the coordinates pretty fast, but the first time should be safe enough. It’ll take her where she needs to go.”

“She could be scattered into atoms, though,” Jack seemed less confident in the mysterious project’s abilities.

Rose bit her lip. “Jack, I wouldn’t ask you to trust me on this unless I really meant it. I _do _know how it works, we developed it years ago in the other Torchwood and tested it. It’s Sontaran, yeah? No modifications?”

A nod.

“Then I don’t see why she wouldn’t be safe. They use it directly for transport, so it should be secure. For now, though, we have to assume that she can’t communicate with us until she starts a call herself.”

Another nod, this one more decisive. “Oh, where would I be without you, Rosie?” he asked dramatically.

She didn’t bother responding, quite used to her old friend’s antics despite the years of separation. She brought down the laptop’s lid after logging out and turned to the Doctor. “We need the TARDIS,” she said shortly, far more professional and cooler than the Doctor had thought she’d be. He couldn’t exactly blame her.

“Right this way.”

* * *

In Wakanda a decade or so ahead of the other team involved in stopping a reality-shaking event, Loki swore softly. Things had moved incredibly fast, enough that she too found it hard to process everything in an orderly manner, as one was wont to do if they wished to survive a war. Judging by the appearance of Proxima Midnight and Corvus Glaive, as Romanoff’s description suggested, they’d next be headed straight to this rather well-defended country. Loki had to admire the technology that was available here, which was incredibly similar to Asgard.

She’d been delighted to speak to the princess, a teenage genius named Shuri, who had designed and upgraded many of their resources. The young scientist appeared to be equally contented to meet her, especially when she wasn’t met by condescending looks and sneers. Loki found her to be quite excitable, and more than a little blunt, but she appreciated her straightforwardness in the light of avoiding diplomatic ice-breakers.

Shuri had quickly found a way to detach the Mind Stone from Vision, but a few complications had removed all possibilities of considering the option. Wanda Maximoff seemed rather distraught when Vision mentioned the connection of the Stone to his very being, as well as the probable need to destroy it. Loki thought that it was worth a small risk to separate it from him, but didn’t voice her thoughts, knowing how unwelcome they would be. As it was, she wanted nothing to do in particular with the Stone. She’d barely reinforced her telepathic barriers as it was.

Thor somehow noticed her discomfort at being so close to the Mind Stone, and discreetly clapped a hand on her shoulder in reassurance as he passed by her to the king of Wakanda. The two of them had been engaged in rapt conversation of Asgard’s fate after this mess was sorted out, and Loki saw no need to halt that discussion. After all, she hadn’t saved Asgard twice in the last six months only to have them roam across the expanse of the universe searching for a home. By the time Loki and Shuri had found a way to mute the energy signature of the Stone without detaching it from Vision (thus rendering it essentially invisible to Thanos), they too had come to an accord.

Faint shouting became audible through the windows, and a dark veil settled over them all. Loki hadn’t fought in wars before, but she’d been to Midgard during both great wars they’d later dubbed “World Wars”, and she recognised the grim focus in the faces of her allies.

It was time to enter the battlefield.

* * *

Donna leaned against the railing, watching the Doctor and Rose swiftly manipulate the controls of the TARDIS. They operated it with a sort of wordless agreement, smoothly enough for her to have figured out the nature of their partnership even if she hadn’t known it before. She did appreciate how neither of them kept her in the dark, regardless of the way she seemed to be inexperienced – at least, compared to the two of them. She quelled the sharp stab of insecurity ruthlessly by reminding herself that a) the Doctor was at least nine hundred years old, b) he’d travelled with Rose for years before she’d been lost over the Void, and c) Rose worked with the parallel Torchwood, and had likely picked up several skills there.

“Rose,” he said uncertainly, and she looked up at him inquisitively. “You’re not going to like this, but… we have to go to the Shadow Proclamation.”

She groaned. “No, why?”

“They may be able to tell us what exactly is going on, and why the Daleks would be attacking the planet – _again_.”

Rose glanced down at the monitor, which was suddenly displaying results in English, and raised her eyebrow. She pushed it towards the Doctor. “Yeah, I don’t think we have to. These probably show enough.”

Donna frowned. Okay, now she was a bit out of the loop, and she didn’t like it at all. “What’s the Shadow Proclamation?” she asked Rose, since the Doctor was busy squinting at the results.

“Fancy name for intergalactic police,” she replied. Donna nodded.

“Twenty-seven planets,” the Doctor muttered, half to himself. “Twenty-seven… there’s a pattern here somewhere, I’m just not getting it.” He shifted his sharp gaze to Donna, wordlessly inviting her to inspect the readings. She pushed away from the railing to read over her friend’s shoulder, frowning lightly.

“Callufrax Minor,” she pronounced carefully. “Jahoo, Shallacatop. Are you sure these are the right names?”

Rose snorted.

“Woman Wept, Clom.” She furrowed her brow, sceptical. “Yeah, I’m not sure these are all right.”

“Clom’s gone?” Rose asked at the same time as her comment, and the Doctor said, in unison with her, “Who’d want Clom?”

They all blinked at each other for a moment before returning to the screen. Donna tilted her head, an idea taking shape in her mind…

“Pyrovilia’s on this list!” She pointed at the name, before spotting another familiar one. “And Adipose Three.”

The Doctor seemed to have spotted another name that he recognised. “The Lost Moon of Poosh! Hang on, these disappeared at different times.”

“So the Daleks are stealing planets through time _and _space,” Rose reasoned. “For what, though?”

“I think this might answer that,” the Doctor said, shifting a bit so that Rose could lean over and examine the contents of the screen. The order of planets, which were now arranged graphically as opposed to the list that had been displayed earlier, changed before her eyes.

“Optimum pattern,” she murmured, observing the spherical planets forming an oddly specific shape. “They’re in perfect balance, aren’t they?”

The Doctor nodded, entranced. “Yeah. Look at that, though. It’s gorgeous.”

Donna smacked the back of his head lightly. “Oi, don’t get all _Spaceman_ when the universe is about to end. What does it mean?”

“All those worlds fit together like pieces of an engine. It’s like a powerhouse. What for, though, I’ve no idea.” A thought seemed to strike him, and he turned to face her fully. “There should have been some sort of warning for this, though. Taken a while to prepare. You’d been looking for weird things happening to find me, was there anything else…?”

“Not as strange as you, mate,” she muttered, wracking her brains for other odd phenomena she’d read about on all those websites. More than half of them had been conspiracies and she didn’t half believe those, but there was one…

“Electrical storms, freak weather, patterns in the sky?” the Doctor prompted.

“Don’t prompt me,” she warned. “I don’t think so. Although, there was something about the bees disappearing.”

“The bees disappearing,” the Doctor repeated dryly. Rose elbowed him and glared. “Sorry,” he muttered, slouching back against the console. “That was a bit rude.”

His eyes widened and he shot back upright, crying, “The bees disappearing! Oh, Donna, you’re absolutely brilliant!”

“Why, what’ve bees got to do with the end of the world?”

“I think they were relocating,” Rose said speculatively. “Something like that happened in the other universe too, before the stars started going out. They were probably going back home.”

“Back home where?” Donna narrowed her eyes. “Hang on, are you saying that bees are aliens?”

“Not all of them,” the Doctor said. “But the migrant bees would have felt it. Some sort of danger. They’d have escaped, using the Tandocca Scale. It’s a sort of… wavelength, infinitely small, that they communicate on. The coordinates that Loki gave us, they followed the Scale to Earth. I thought they looked familiar,” he said at last, beaming.

“At least we’re on Earth,” he countered. She conceded that point to him.

“Right, so what’s our plan now?” she asked, before all the lights went out. The bluish green light of the Time Rotor was extinguished as well, and she had to blink a few times to get used to the dark.

“It’s…” Rose started, looking a little nervous, but didn’t bother finishing her sentence.

“Well, that’s new. Well, not particularly _new_, but. New.” The Doctor fiddled with the controls for a bit, to no avail. He growled, suddenly frustrated, and moved to wrench open the door. Rose and Donna spotted what he’d missed and hauled him back immediately, effectively stopping what would have been a fall from an awfully large height. Donna released the Doctor’s coat, and he absently straightened it as she peeked over the edge.

“Looks like some sort of… transport beam,” she observed.

“I think that’s what it is,” the Doctor said, leaning out more carefully to look at the ship above them. “The Daleks, obviously.”

Rose and Donna shot him twin looks of disbelief. He ran a hand through his hair, trying to ignore the dread that was slowly overpowering his thoughts. He couldn’t afford to panic now, despite how his old enemies seemed to be resurfacing every time they were stopped. He hoped that this time would be more permanent.

The alternative was simply unthinkable.


	4. Chapter 4

The lights blinked back on, weak, but there. The Doctor lunged for the controls immediately, signalling with a wordless cry for Rose to join him and move them into the Time Vortex. A few seconds later, they were floating freely with their systems back online. Donna watched the pair work smoothly together, with the practised ease of partners who were incredibly compatible with each other. She felt the familiarity too, this time, without the sting of realisation that she didn’t know enough to help them – she knew that she was _undoubtedly _part of their strange family.

The pair ran back and forth, tossing levers with a gentle carelessness, spinning dials, and pushing buttons. The floor beneath Donna settled into a comfortable hum, and she knew that they’d reached the Time Vortex. The monitor flickered to life and she stepped forward immediately, ready to receive the message that the TARDIS would translate for her now. She’d felt this thrill before, during her time with the Doctor, but only now did she fully understand why the Doctor called those who travelled with him his _companions_ – they were so much more than assistants, or passengers; they stood by his side and helped him (oftentimes it was the other way around, even) and did good in the universe. Donna wouldn’t call _everyone_ who’d travelled with the Doctor his partners – that could really only be Rose’s title – but companion came pretty close.

The screen split into four sections. Jack was on one of them, as were two women she didn’t know, and –

“Harriet Jones, former Prime Minister,” said Harriet Jones.

“Yeah, I know who you are,” Donna said automatically, and Jack snorted.

“Are the Doctor and Rose with you? They’ll need to hear this too,” he said.

The couple had exchanged a Look when Harriet Jones had spoken up, and they made their way over to the monitor. The Doctor, with his height, stood behind Rose and Donna to peer over their shoulders, able to watch without blocking their view.

“Rose, this is Martha,” Jack introduced, and the dark-haired lady on the top left wearing what looked to be a soldier’s uniform waved at her.

“Martha, it’s good to see you,” Rose said. “Where are you?”

“Indigo works on intentions,” she said excitedly. Rose nodded. “I ended up in the one place I wanted to be – at my mum’s place. Then the laptop turned on, all by itself.”

“That would be me,” the former prime minister said. “Doctor, Rose, I assume you already know Sarah Jane Smith?”

“Yeah,” Rose said, and Donna could hear the grin in her tone. “I didn’t expect to see you here, though I’m not surprised.”

Sarah Jane laughed. “It’s good to know that you’ve made it back,” she said warmly.

“I’ve been following you on your work,” Jack said. “Nice work with the Slitheen.”

The slightest of frowns made its way to Sarah Jane’s forehead. “I’ve been staying away from your lot,” she said, nodding towards a young boy next to her. “Too many guns.”

“All the same, might I say, looking good, ma’am?”

The Doctor rolled his eyes, though he smiled at Sarah Jane’s enthusiastic reply.

“Not now, Captain,” Harriet Jones interrupted.

“Er, yeah,” the Doctor said, realising that Donna barely knew anyone here. “Everyone, this is Donna Noble. Donna, That’s Jack, Martha, and Sarah Jane.” She nodded. “You already know Harriet Jones.”

“Yeah,” she said, trying to wrap her head around the oddness of the situation. Rose patted her on the shoulder in solidarity of someone caught in the middle of a seemingly unfathomable situation that could really only be a by-product of travelling with the Doctor, because why else would she be speaking to the _former Prime Minister of her country_?

Harriet Jones squinted at her screen. “Everyone, this is the Subwave Network, a sentient piece of software programmed to seek out anyone and everyone who can help the Doctor.”

“Handy, that,” the Doctor muttered. “Did you create it?”

“I did develop it, yes,” she said proudly. “It was created by the Mr. Copper Foundation, and is undetectable to anyone who isn’t meant to know of it.”

Everyone looked impressed. “Does this mean others will be contacted too?” Donna asked. “I mean, the Doctor has more friends who’d want to help us.”

Harriet tilted her head. “It could, theoretically speaking. They’d not even have to be in the same part of the timeline.”

The Doctor’s expression clouded. “That opens a risk of running into other versions of me, if they’re still travelling when you call.”

Harriet nodded, only half listening. “That’s the thing, Doctor – when I said it was _sentient_, I mean that it senses these things. I wasn’t fully aware of how many of you would be contacted, when I started the program.”

Rose hummed. “That would mean it sends out signals whenever someone becomes available.”

“Yes, it does. But what does that-”

“_Exterminate_!”

* * *

Elsewhere and elsewhen, the army of Wakandans and heroes (and otherworldly antiheroes, in Loki’s case) lay exhausted in the rubble-filled palace. The whole country was under siege, with evacuation plans ready to be exacted when the time came. _If_ the time came, Shuri corrected immediately. She had not been battling in the fields, but observing and acting from behind the walls of her lab. Though she was far from useless in combat – few people knew that she was an excellent sharpshooter, and she’d developed artillery that would be effective enough over a large distance.

She could count the number of missed shots in her life on one hand.

Right now, though, she was working feverishly with the Aesir mage - who seemed to be thoroughly drained - to find the keeper of the Time Stone, one Stephen Strange. She’d learned from Loki that there were protocols to be followed in case of such an event, though this was on a far more massive scale than any situations she’d had in mind when she’d written them. Loki apparently also knew one of the inhabitants of the New York Sanctum, a man named Wong who knew when protocol was to be followed and when it could be overlooked. Shuri also found out that despite knowing the Ancient One (their former leader of sorts who had stopped her aging until her recent passing) for a relatively long time, Wong was the one Loki had trusted to guard the Sanctum.

“You said he has the Time Stone, couldn’t he just use it to hide outside the flow of events?” Shuri asked. She understood perfectly the mechanics of the Time Stone, but the idea of magic was still odd enough for her to be more questioning of its boundaries and limits (with hypothetical hybrid spells and the like).

“You’d have to be in between universes – because the multiverse theory is true, by the way – for that to be pulled off well. Otherwise anyone who was sensitive to that type of energy could follow its trace. No, Strange has hidden the Time Stone well and not used his powers to move.”

Shuri hummed. “Do you-”

A monitor next to her flickered to life. “What the-”

Five smaller screens, evidently some sort of group call, blinked into view. Some of them were blurrier than the rest, as though the recording device wasn’t particularly clear enough. Shuri knew that the video feed from her lab would be crystal clear, though she shifted her stance subtly. Loki, however, seemed to lose all traces of exhaustion and surged forward.

“Doctor!”

“Loki?” A man with spiky brown hair narrowed his eyes at the screen, looking rather shaken about... something. “I thought you were – oh, it connects into the future, how brilliant is that?” he turned to a blonde woman next to him, sounding delighted.

The woman, however, looked slightly troubled. “Er, yeah. I know you’re in trouble at your end, but we really need your help.”

“Rose, we’re in the middle of something that could potentially end the universe,” Loki said, slumping back.

“So are we, only it’s the whole multiverse,” the blonde – Rose, apparently – countered.

Loki groaned and quickly introduced them all to Shuri. She listened to their predicament, noticing the already wan trickster pale even more when they explained that something called _the Daleks_ were involved in the mess. She tilted her head. “You know, with the Infinity Stones, you could lock them all into some sort of pocket dimension eternally. The Daleks, and Thanos’… hoardes.”

Loki frowned, though she accepted the young scientist’s solution as a quick and effective means of ending both events. “Be that as it may, we only still have Space and Mind. Reality and Power are with Thanos, and we don’t know where Soul and Time are.”

A ring of sparks appeared in the air, growing bigger till a man wearing robes and a cloak stepped out. No, not robes – it looked somewhat like martial arts gear. “I believe I can help you with that,” the new man said.

Loki responded by punching him in the jaw.

* * *

Rose winced. “Whew, what’d he do to Loki to get _that_ reaction?”

Donna shrugged. “Dunno, but from the one time I’ve met them – her? – it must’ve been _something_.”

The Doctor hummed an affirmative. “Well. She prefers to decimate people verbally rather than resorting to violence. Which doesn’t mean she can’t gut him with a butter knife.”

Donna grinned. “Well, I wouldn’t mind learning that.”

Loki glanced up from the man, who was now crumpled on the floor nursing his face, to the monitor. “I think Valkyrie would love to help you with that,” she commented, and looked back rather derisively at Strange.

“Now, I’d like to know why you showed up now, instead of _before_ the battle.” Her voice had slipped into a low growl, fuelled by her anger and frustration from the day’s events. Shuri rested a hand on her arm, though Rose could tell that it was more in solidarity than to calm her friend.

“The timelines,” the man explained. “All of this needed to happen this way.”

“You _charlatan_,” Loki hissed along with some choice words in her native tongue, “Time doesn’t flow in a single stream. This isn’t a fixed event, everything’s in flow. You didn’t even bother following the right protocol for when the Stone was in danger, by warding yourself so thoroughly.”

“I thought that wards-”

“Were to protect you, but not make you undetectable to other sorcerers! And don’t excuse yourself by calling on a single timeline, when you decided to use the Stone at your whim, _while warded_, so that the Stone would be free to be taken had anything gone wrong! A truly stellar plan,” she concluded scathingly.

He looked stunned. “As keeper of the Stone, though-”

“I could strip you of your rank right now,” Loki said icily. “The Stonekeeper has duties to fill, and you’ve neglected them for far longer than you should have. Now, since you’re here, I’d like for you to hand it over so that we can proceed with the next part of the plan we – Shuri was coming up with to save the multiverse.”

Strange handed it over wordlessly, more than a little cowed by Loki’s tirade. Loki inspected it and slid the necklace over into the case that held the Tesseract. She turned towards the screen.

“Couldn’t the plan be possible with just the Space and Time Stones, though?” Shuri asked. “I mean, you _do_ have such a ship at your end.”

“I could,” the Doctor mused, “if I recalibrated the TARDIS to accept the additional power from the Stones. Well, we’d really need people who can use them without burning up into husk for that to happen.”

Loki smirked. “I believe Strange – incompetent fool he is – and I can manage that.”

Shuri snorted, though she’d forever deny it, when the sorcerer started to splutter.

The Doctor tilted his head, interested in another train of thought. “You’re a Stonekeeper?”

Loki nodded. “I was. Ages ago, really. I was tasked with bringing the Space Stone to Midgard for safekeeping, though the mortals have failed in that rather spectacularly.”

“Oi, the Stone would’ve remained secret if it weren’t for some red-faced nazi,” Donna protested.

“And the Kree,” Rose added. “We helped Carol with that, didn’t we? In finding the Skrulls a new home?”

The Doctor hummed.

“I was more talking about how the humans at SHIELD managed to do the one thing they were supposed to avoid – attracting Thanos’ attention – by experimenting on the thing in question,” Loki said dryly.

“You know, Torchwood’s a lot more organised than that,” Jack commented.

Rose nodded absently in agreement. “Well, then, I suppose we could get started.”

* * *

The next three hours were spent in the calculation of what exactly it would take to combine and amplify the powers of the TARDIS and two Infinity Stones. Shuri had come to the conclusion that all the preparation needed to be done only on the part of the TARDIS, so the others got some amount of rest as the trio flitted about the console, readying their Time Ship to receive the powers of two primordial energy stones. Loki, for the time being, had set aside her differences with Strange and was discussing the best way to collaborate and reach out across into the Time Vortex, and into their specific timeline, without getting caught in any other, when Harriet Jones made a suggestion.

“If I may,” she said. “Harriet Jones, former Prime Minister,” she introduced.

“We know who you are,” Loki said automatically, glancing back at Strange. “You were saying?”

“The Subwave Network could reach out across the timeline as it did for this call, and you could retrace the TARDIS using the signal it emits.”

“Or we could meet halfway,” the Doctor called, after muttering a string of curses when he slammed his head against the console as he stood up. “I have the code, but it would need some very fast typing.”

Rose frowned. “You’ve flown the TARDIS for over nine centuries,” she commented.

He raised a brow. “Rose, I’m good, but I’m not _that_ good. There’s less coding and more rewiring to be done, actually.”

Donna grinned. “Where’s the code?”

She shoved the Doctor aside, once he showed it to her. She glanced up at the monitor. “So, do I start now?”

Harriet Jones nodded. Donna cracked her knuckles. “Right.”

She flipped the screen that dropped down with the code, spilling the display into two halves with a small flick of her wrist (holo-screens or whatever they were called shouldn’t have been all that normal for her, but she’d seen stranger and less practical things) and swiftly typing in the code in the latter half. It was unfortunately not possible to copy as it had to be updated and changed slightly, and Donna had studied enough sequences, and memorised the entire Dewey Decimal System to know what came next.

The Doctor stood in shock as Donna’s fingers blurred across the virtual keyboard, expertly changing the values as though she’d been doing it all along. Harriet Jones called out more changes and Donna incorporated them in without stopping for a second. The only sign that she was aware of her surroundings was the fact that she still flinched when a nearby control sparked, going into overload.

She was done in less than five minutes, leaving Rose and the Doctor in the dust and awe at her speed.

“Now that’s how you do it,” she said triumphantly, stepping away from the receding screen.

“How…”

“Super temp,” she said nonchalantly.

“That was brilliant, Donna,” Rose murmured, clapping a hand on her shoulder. Donna smiled humbly.

“Thanks.”

Harriet cleared her throat, looking somewhat impressed herself. “I believe we have two apocalypses to avert,” she interrupted mildly.

Everyone immediately leaped into action. They’d all been given a chance to save two universes (objectively speaking. What they _did_ have was a chance to fix two timelines), and there was no way they were letting it go to waste.


	5. Chapter 5

Thor had been in several battles before, and more than a single war. Given his experience, he would say that it was not the fighting, rather the aftermath and what was left behind, that made the whole affair so terrible a concept. Even his youth when he longed to quench his thirst, he wished not for the massive destruction of war but more the smaller skirmishes which could only be stopped with punches. He’d usually left the diplomacy to his brother, but one didn’t spend most of life around someone who had earned the title _Silvertongue_ without learning a few useful things in the process.

This was why he didn’t mind sitting at various meetings to discuss the future of the Asgardians the Doctor had rescued from deep space using the now amplified TARDIS. Together, he and Loki had managed to wrangle a plot of land that only could be called a town from the UN representatives. The Norwegian Prime Minister was more than willing to offer them some area which lay outside the touristic routes while being accessible. It so happened to be caught in the middle of a coastline and forest, so they agreed to it immediately and heartily.

Thor couldn’t entirely understand what the paired Stones and TARDIS had done, but he was grateful. His sister was speaking with the Doctor, Donna, and someone named Rose, about them being able to pass into the parallel universe if they wished without causing any damage. Rose seemed to light up at that and thanked her profusely – Thor could barely make out the words – and asked the Doctor if he’d visit her family there. All around, he surmised, there were happy faces. He had no doubt that the battle strain would crash onto him in a few days’ time, but he’d celebrate with the rest until it did.

However, there were still a few things that could take him by surprise, and that evening when he sat on the roof of one of the apartment complexes that T’Challa had directed them to was one of them. He’d been there since the sun set, watching the stars silently. He was thoroughly unprepared to find a shadow momentarily cross his vision and settle next to him. He turned his head slightly, not yet alarmed, to find Loki lying next to him, looking up at the pinpricks of light above them.

“Do you ever think about how one of those-” she gestured vaguely at the sky with her free hand – “was the furnace that forged Mjolnir?”

“And the Gauntlet besides,” Thor replied. “No, actually, I hadn’t.”

Loki hummed. “Technically, though, Nidavellir doesn’t even count as a star. It’s simply the closest to it.”

“What would you call it, then?” It was a conversation they’d had many times, and Thor found the familiar dialogue comforting him and distracting him away from the solemn musing he’d been doing before his sister had arrived.

“You know as well as I,” Loki said, stretching out fully. “A star going supernova caught in a Void brace.”

“I didn’t know they were called Void braces,” Thor said absently, following with his eyes the path of a comet – which he knew was really the remains of the ship that he and Loki had just reduced to fragments a week ago.

“It’s a terrible name, and I made sure that the Doctor knew it.”

“I never much liked our own word for it either,” Thor added. “Did he name the contraption?”

Loki shrugged. “Honestly, I doubt even he knows.”

* * *

_“Come get me when you’re both ready. Just don’t leave me here for more than twelve hours.”_

Donna had gone to visit her grandfather and her mother, leaving the Doctor and Rose with as much time as they liked to reunite. She’d waggled her eyebrows a bit as she said it, but the Doctor had only rolled his eyes. Yeah, they had a lot to talk about, but that was about the only thing happening that night. Well, that and some snuggling, hopefully. They made their way over to their joint suite, which the Doctor hadn’t used since… well. Rose squeezed his arm and he smiled at her, nervous, mind racing a thousand miles a minute.

“I’m going to take a shower,” Rose murmured, “and once I’ve changed we cuddle and talk on the bed.”

He nodded mutely, his thoughts picking up the pace a notch. The ‘notch’ being a few five hundred more miles than a moment ago. He decided to change out of his suit as well, slipping into the other ensuite bathroom that was meant for the very purpose of freshening up after long adventures, to reduce the overall waiting time. Post-potentially-apocalyptic adventures usually had a routine to them too, though they weren’t as frequent as some others. The Doctor pulled on a soft cashmere jumper and linen trousers that the TARDIS had pulled out of the wardrobe for him, and he rested a hand against the wall in silent thanks.

Rose stepped out a few minutes later, drying her hair on a towel, and the Doctor felt the agony of their separation meting away as though it had never happened. He stepped forward automatically and she handed the towel to him, sitting down before him on the bed. He sat behind her, carefully drying her hair with long-practiced movements. A few years away from her were not nearly enough to soften a Time Lord’s memories – or, the Doctor’s memories of his love.

The motions eventually let both of them into a silent, relaxed state. The Doctor was not quite prepared for Rose to interrupt the peaceful bubble they’d created, and started rather badly when she spoke.

“I never thought, on our first day back together, we’d stop two apocalypses together,” she said. Her voice was low enough to nearly be a whisper, but to the Doctor it sounded like a shout from across a street. Something he would always hear and turn towards, regardless of the volume of her call.

“Sounds exactly like us, though,” he replied, equally soft. His hands didn’t still, and he set aside the towel to card his fingers through her strands, lightly removing the tangles.

Rose hummed. “Seems like an enormous coincidence,” she commented.

The Doctor chuckled. “If a coincidence leads me back to you, love, I wouldn’t really complain.”

“Hmm. True.” She turned to face him, and he dropped his hands to his lap. They gazed at each other for a few moments, before she cupped his face in her hands and pulled him forward into a gentle, chaste kiss. The Doctor half-smiled against her lips and wrapped his arms around her. As opposed to the passionate reunion in the streets of London, they were the very picture of tender.

Rose broke off the kiss and snuggled close to him, not leaving his hug. They manoeuvred carefully to rest against the padded headboard of the bed, which they’d selected with this very situation in mind. The Doctor had told her early on that he wished to go no further than chaste touches and Rose had only been supportive since. She sighed contentedly and relaxed fully against him. He automatically dipped his head to press a kiss to her brow.

“I don’t entirely believe that we’re here,” he muttered after a while.

Rose nodded. “Neither do I,” she admitted. “It’s… I’ve dreamt about it for so long that now that it’s true, I don’t know what to think.”

The Doctor made a small, strangled sound at the back of his throat. Rose chuckled, and rested her head against his chest. “Yeah, that’s it.”

* * *

Thor leaned back in his chair and rubbed his eyes tiredly. He’d been filling out forms all day, with much-needed help from his sister. Loki huffed and sank against the couch cushions, yanking a blanket over herself. Thor raised an eyebrow. “I thought you couldn’t feel cold?”

“I like the material,” she grumbled. “Now shut up and sit down. You won’t get anything done today with how antsy you are, so we might as well stop trying to work and watch something.”

Well, this was a first. Thor had watched a few movies and TV shows with Jane and Darcy years ago, but he wasn’t all that familiar with the wide range of genres that were available to them. Loki would be more knowledgeable of it, though, he supposed, having been to Earth several times in the recent past.

“Okay,” he said, lowering himself onto the other side of the couch and tugging loose the spare blanket at his sister’s feet. He drew the soft fleece about him, settling back comfortably. “What are we watching?”

Loki shrugged. “Do you have any favourites?”

Thor thought back. “Pride and Prejudice. The 2005 one. But I wanted to try something new.”

“Action movies are out, I’d rather not relive a battle just when we’re done,” Loki said dryly. Thor nodded, he wasn’t so fond of action movies (which Darcy had shown him a few times) for much the same reasons. It was too much like listening to old bards recite the legends of warriors repeatedly at a tavern.

“Comedy?”

His sister wrinkled her nose. “Perhaps some other time.” Her eyes lit up and she shot forward. “Heist movies!”

“What?”

“Trust me, brother,” she said, already pulling one up onto the screen, “You’ll really enjoy this.”

Thor leaned over and flipped the light switch. He had to blink a few times as the dark of the room caused the glare from the TV screen became even brighter, but his eye adjusted quickly. “Remind me to get a bionic eye made,” he muttered. “This lack of depth perception is bordering on ridiculous. Loki chuckled, but didn’t say anything.

_“I’m going to flip through this deck,” _the movie began. “_And I want you to see one card…”_

* * *

A few months later, a blue box appeared with a great rasping noise. Thor was prepared for it this time, because Loki had told him to expect it one day. They were still building the houses in the town they called New Asgard (which Thor had wanted to name something else in their native tongue, but Loki and Brunnhilde had already written off the name for without consulting him), so those houses which hadn’t been entirely constructed yet had rented hotel suites to stay in for a while.

Thor had been going through a list of complaints from those few families who were left (their construction was nearly complete thanks to the number of mages who’d offered to help) waiting for their cottages and cabins to be open for stay when he heard the knock on the door. He’d opened it to the Doctor and Rose amicably chatting with Loki, and had invited the couple inside eagerly.

His sibling had joined them a minute or so later, setting aside the new pile of books they’d gone out to buy that morning. The rest of the morning, and much of the afternoon, flew by in catching up with each other.

“To be honest, I’m still not sure what the TARDIS and Stones _did_,” the Doctor said. “Well. Not that I’m not grateful, but I don’t like not knowing.”

Loki shrugged. “Perhaps it’s for the best. We can’t have anyone else finding out,” they said.

The Doctor hummed. “That’s fair.”

Meanwhile, Rose and Thor had gotten into a lively discussion about what facilities to include in their new home. “A mental health facility is a must,” Rose said, to which Thor agreed heartily.

“We planned on an orphanage as well, since most of the children lost family on Asgard.” A pang of sorrow and grief tugged at him and Rose nodded sympathetically.

“A school and university,” she suggested next, and the rest of their talk was about what sort of education they’d need to include now that they were an active community in Midgard.

When they left that evening with a promise to visit again, Thor helped Loki sort out the books they’d bought. It was a relatively small pile as opposed to some of their other trips to the bookshop, and Thor voiced the question of where they were going to find space for more books.

“I’ll sacrifice my room,” Loki said without hesitation, adding _A Brief History of Time_ to the nonfiction pile. “It won’t hurt to sleep on the couch in the living room.”

Thor snorted, they knew perfectly well that that wasn’t necessary, seeing as they’d set aside a room entirely as a library of their own (which was already partly filled with Loki’s old manuscripts and books he’d saved from Asgard, and the ones they’d bought since arriving at Earth). Still, he appreciated the sarcastic humour, which he felt was in short supply these days as their work only mounted exponentially with the construction plans for basic facilities and houses coming close to an end.

He picked up another book which had a rather lovely cover page, blue with embossed silver patterns. The title was awfully familiar, though. “Loki, haven’t you already read this series?”

Loki glanced at the title. “It’s Pullman, and have you seen that edition? There was no way I _wasn’t_ going to buy it.”

Thor grunted, but didn’t protest. “What about this one?” He lifted up another book by the same author.

“_La Belle Sauvage_ is a companion book to the series,” Loki said indignantly. “I’ve been meaning to read it for ages, something you should probably get around to as well.”

Thor chuckled. “Of course, _søsken_.”

Loki ignored him and continued sorting out the books. Thor returned to the task as well, idly thinking that if this was what he would have to do for the next millennia, it didn’t seem so bad after all.

**Notes for the Chapter:**

> A few short notes:  
-The movie which they watched is _Now You See Me_, which is my favourite heist movie  
-_His Dark Materials_ is a wonderful book series by Philip Pullman and is now getting a TV adaptation (which will air in November), and _The Book of Dust_ is its companion series  
-'Søsken' in Norwegian means 'sibling', which seemed like an apt way for Thor to address Loki when they go by they/them pronouns
> 
> If you're reading this, thank you for sticking till the end!


End file.
